Merge "Add CompatScaleProvider interface" into main

6 files changed, 482 insertions, 35 deletions

diff --git a/core/java/android/app/ActivityThread.java b/core/java/android/app/ActivityThread.java
index 39589fa93149..f28b4b4eb207 100644
--- a/core/java/android/app/ActivityThread.java
+++ b/core/java/android/app/ActivityThread.java
@@ -36,7 +36,6 @@ import static android.view.Display.INVALID_DISPLAY;
 import static android.window.ConfigurationHelper.freeTextLayoutCachesIfNeeded;
 import static android.window.ConfigurationHelper.isDifferentDisplay;
 import static android.window.ConfigurationHelper.shouldUpdateResources;
-
 import static com.android.internal.annotations.VisibleForTesting.Visibility.PACKAGE;
 import static com.android.internal.os.SafeZipPathValidatorCallback.VALIDATE_ZIP_PATH_FOR_PATH_TRAVERSAL;
 
@@ -1286,8 +1285,13 @@ public final class ActivityThread extends ClientTransactionHandler
         }
 
         private void updateCompatOverrideScale(CompatibilityInfo info) {
-            CompatibilityInfo.setOverrideInvertedScale(
-                    info.hasOverrideScaling() ? info.applicationInvertedScale : 1f);
+            if (info.hasOverrideScaling()) {
+                CompatibilityInfo.setOverrideInvertedScale(info.applicationInvertedScale,
+                        info.applicationDensityInvertedScale);
+            } else {
+                CompatibilityInfo.setOverrideInvertedScale(/* invertScale */ 1f,
+                        /* densityInvertScale */1f);
+            }
         }
 
         public final void runIsolatedEntryPoint(String entryPoint, String[] entryPointArgs) {
diff --git a/core/java/android/content/res/CompatibilityInfo.java b/core/java/android/content/res/CompatibilityInfo.java
index 08ba5b6c268c..f929c1f03c87 100644
--- a/core/java/android/content/res/CompatibilityInfo.java
+++ b/core/java/android/content/res/CompatibilityInfo.java
@@ -100,7 +100,7 @@ public class CompatibilityInfo implements Parcelable {
      * The effective screen density we have selected for this application.
      */
     public final int applicationDensity;
-    
+
     /**
      * Application's scale.
      */
@@ -112,9 +112,27 @@ public class CompatibilityInfo implements Parcelable {
      */
     public final float applicationInvertedScale;
 
+    /**
+     * Application's density scale.
+     *
+     * <p>In most cases this is equal to {@link #applicationScale}, but in some cases e.g.
+     * Automotive the requirement is to just scale the density and keep the resolution the same.
+     * This is used for artificially making apps look zoomed in to compensate for the user distance
+     * from the screen.
+     */
+    public final float applicationDensityScale;
+
+    /**
+     * Application's density inverted scale.
+     */
+    public final float applicationDensityInvertedScale;
+
     /** The process level override inverted scale. See {@link #HAS_OVERRIDE_SCALING}. */
     private static float sOverrideInvertedScale = 1f;
 
+    /** The process level override inverted density scale. See {@link #HAS_OVERRIDE_SCALING}. */
+    private static float sOverrideDensityInvertScale = 1f;
+
     @UnsupportedAppUsage
     @Deprecated
     public CompatibilityInfo(ApplicationInfo appInfo, int screenLayout, int sw,
@@ -123,17 +141,24 @@ public class CompatibilityInfo implements Parcelable {
     }
 
     public CompatibilityInfo(ApplicationInfo appInfo, int screenLayout, int sw,
-            boolean forceCompat, float overrideScale) {
+            boolean forceCompat, float scaleFactor) {
+        this(appInfo, screenLayout, sw, forceCompat, scaleFactor, scaleFactor);
+    }
+
+    public CompatibilityInfo(ApplicationInfo appInfo, int screenLayout, int sw,
+            boolean forceCompat, float scaleFactor, float densityScaleFactor) {
         int compatFlags = 0;
 
         if (appInfo.targetSdkVersion < VERSION_CODES.O) {
             compatFlags |= NEEDS_COMPAT_RES;
         }
-        if (overrideScale != 1.0f) {
-            applicationScale = overrideScale;
-            applicationInvertedScale = 1.0f / overrideScale;
+        if (scaleFactor != 1f || densityScaleFactor != 1f) {
+            applicationScale = scaleFactor;
+            applicationInvertedScale = 1f / scaleFactor;
+            applicationDensityScale = densityScaleFactor;
+            applicationDensityInvertedScale = 1f / densityScaleFactor;
             applicationDensity = (int) ((DisplayMetrics.DENSITY_DEVICE_STABLE
-                    * applicationInvertedScale) + .5f);
+                    * applicationDensityInvertedScale) + .5f);
             mCompatibilityFlags = NEVER_NEEDS_COMPAT | HAS_OVERRIDE_SCALING;
             // Override scale has the highest priority. So ignore other compatibility attributes.
             return;
@@ -181,7 +206,8 @@ public class CompatibilityInfo implements Parcelable {
             applicationDensity = DisplayMetrics.DENSITY_DEVICE;
             applicationScale = 1.0f;
             applicationInvertedScale = 1.0f;
-
+            applicationDensityScale = 1.0f;
+            applicationDensityInvertedScale = 1.0f;
         } else {
             /**
              * Has the application said that its UI is expandable?  Based on the
@@ -271,11 +297,16 @@ public class CompatibilityInfo implements Parcelable {
                 applicationDensity = DisplayMetrics.DENSITY_DEVICE;
                 applicationScale = 1.0f;
                 applicationInvertedScale = 1.0f;
+                applicationDensityScale = 1.0f;
+                applicationDensityInvertedScale = 1.0f;
             } else {
                 applicationDensity = DisplayMetrics.DENSITY_DEFAULT;
                 applicationScale = DisplayMetrics.DENSITY_DEVICE
                         / (float) DisplayMetrics.DENSITY_DEFAULT;
                 applicationInvertedScale = 1.0f / applicationScale;
+                applicationDensityScale = DisplayMetrics.DENSITY_DEVICE
+                        / (float) DisplayMetrics.DENSITY_DEFAULT;
+                applicationDensityInvertedScale = 1f / applicationDensityScale;
                 compatFlags |= SCALING_REQUIRED;
             }
         }
@@ -289,6 +320,8 @@ public class CompatibilityInfo implements Parcelable {
         applicationDensity = dens;
         applicationScale = scale;
         applicationInvertedScale = invertedScale;
+        applicationDensityScale = (float) DisplayMetrics.DENSITY_DEVICE_STABLE / dens;
+        applicationDensityInvertedScale = 1f / applicationDensityScale;
     }
 
     @UnsupportedAppUsage
@@ -528,7 +561,8 @@ public class CompatibilityInfo implements Parcelable {
     /** Applies the compatibility adjustment to the display metrics. */
     public void applyDisplayMetricsIfNeeded(DisplayMetrics inoutDm, boolean applyToSize) {
         if (hasOverrideScale()) {
-            scaleDisplayMetrics(sOverrideInvertedScale, inoutDm, applyToSize);
+            scaleDisplayMetrics(sOverrideInvertedScale, sOverrideDensityInvertScale, inoutDm,
+                    applyToSize);
             return;
         }
         if (!equals(DEFAULT_COMPATIBILITY_INFO)) {
@@ -548,15 +582,17 @@ public class CompatibilityInfo implements Parcelable {
         }
 
         if (isScalingRequired()) {
-            scaleDisplayMetrics(applicationInvertedScale, inoutDm, true /* applyToSize */);
+            scaleDisplayMetrics(applicationInvertedScale, applicationDensityInvertedScale, inoutDm,
+                    true /* applyToSize */);
         }
     }
 
     /** Scales the density of the given display metrics. */
-    private static void scaleDisplayMetrics(float invertedRatio, DisplayMetrics inoutDm,
-            boolean applyToSize) {
-        inoutDm.density = inoutDm.noncompatDensity * invertedRatio;
-        inoutDm.densityDpi = (int) ((inoutDm.noncompatDensityDpi * invertedRatio) + .5f);
+    private static void scaleDisplayMetrics(float invertScale, float densityInvertScale,
+            DisplayMetrics inoutDm, boolean applyToSize) {
+        inoutDm.density = inoutDm.noncompatDensity * densityInvertScale;
+        inoutDm.densityDpi = (int) ((inoutDm.noncompatDensityDpi
+                * densityInvertScale) + .5f);
         // Note: since this is changing the scaledDensity, you might think we also need to change
         // inoutDm.fontScaleConverter to accurately calculate non-linear font scaling. But we're not
         // going to do that, for a couple of reasons (see b/265695259 for details):
@@ -570,12 +606,12 @@ public class CompatibilityInfo implements Parcelable {
         //    b. Sometime later by WindowManager in onResume or other windowing events. In this case
         //       the DisplayMetrics object is never used by the app/resources, so it's ok if
         //       fontScaleConverter is null because it's not being used to scale fonts anyway.
-        inoutDm.scaledDensity = inoutDm.noncompatScaledDensity * invertedRatio;
-        inoutDm.xdpi = inoutDm.noncompatXdpi * invertedRatio;
-        inoutDm.ydpi = inoutDm.noncompatYdpi * invertedRatio;
+        inoutDm.scaledDensity = inoutDm.noncompatScaledDensity * densityInvertScale;
+        inoutDm.xdpi = inoutDm.noncompatXdpi * densityInvertScale;
+        inoutDm.ydpi = inoutDm.noncompatYdpi * densityInvertScale;
         if (applyToSize) {
-            inoutDm.widthPixels = (int) (inoutDm.widthPixels * invertedRatio + 0.5f);
-            inoutDm.heightPixels = (int) (inoutDm.heightPixels * invertedRatio + 0.5f);
+            inoutDm.widthPixels = (int) (inoutDm.widthPixels * invertScale + 0.5f);
+            inoutDm.heightPixels = (int) (inoutDm.heightPixels * invertScale + 0.5f);
         }
     }
 
@@ -594,38 +630,55 @@ public class CompatibilityInfo implements Parcelable {
         }
         inoutConfig.densityDpi = displayDensity;
         if (isScalingRequired()) {
-            scaleConfiguration(applicationInvertedScale, inoutConfig);
+            scaleConfiguration(applicationInvertedScale, applicationDensityInvertedScale,
+                    inoutConfig);
         }
     }
 
     /** Scales the density and bounds of the given configuration. */
-    public static void scaleConfiguration(float invertedRatio, Configuration inoutConfig) {
-        inoutConfig.densityDpi = (int) ((inoutConfig.densityDpi * invertedRatio) + .5f);
-        inoutConfig.windowConfiguration.scale(invertedRatio);
+    public static void scaleConfiguration(float invertScale, Configuration inoutConfig) {
+        scaleConfiguration(invertScale, invertScale, inoutConfig);
+    }
+
+    /** Scales the density and bounds of the given configuration. */
+    public static void scaleConfiguration(float invertScale, float densityInvertScale,
+            Configuration inoutConfig) {
+        inoutConfig.densityDpi = (int) ((inoutConfig.densityDpi
+                * densityInvertScale) + .5f);
+        inoutConfig.windowConfiguration.scale(invertScale);
     }
 
     /** @see #sOverrideInvertedScale */
     public static void applyOverrideScaleIfNeeded(Configuration config) {
         if (!hasOverrideScale()) return;
-        scaleConfiguration(sOverrideInvertedScale, config);
+        scaleConfiguration(sOverrideInvertedScale, sOverrideDensityInvertScale, config);
     }
 
     /** @see #sOverrideInvertedScale */
     public static void applyOverrideScaleIfNeeded(MergedConfiguration mergedConfig) {
         if (!hasOverrideScale()) return;
-        scaleConfiguration(sOverrideInvertedScale, mergedConfig.getGlobalConfiguration());
-        scaleConfiguration(sOverrideInvertedScale, mergedConfig.getOverrideConfiguration());
-        scaleConfiguration(sOverrideInvertedScale, mergedConfig.getMergedConfiguration());
+        scaleConfiguration(sOverrideInvertedScale, sOverrideDensityInvertScale,
+                mergedConfig.getGlobalConfiguration());
+        scaleConfiguration(sOverrideInvertedScale, sOverrideDensityInvertScale,
+                mergedConfig.getOverrideConfiguration());
+        scaleConfiguration(sOverrideInvertedScale, sOverrideDensityInvertScale,
+                mergedConfig.getMergedConfiguration());
     }
 
     /** Returns {@code true} if this process is in a environment with override scale. */
     private static boolean hasOverrideScale() {
-        return sOverrideInvertedScale != 1f;
+        return sOverrideInvertedScale != 1f || sOverrideDensityInvertScale != 1f;
     }
 
     /** @see #sOverrideInvertedScale */
-    public static void setOverrideInvertedScale(float invertedRatio) {
-        sOverrideInvertedScale = invertedRatio;
+    public static void setOverrideInvertedScale(float invertScale) {
+        setOverrideInvertedScale(invertScale, invertScale);
+    }
+
+    /** @see #sOverrideInvertedScale */
+    public static void setOverrideInvertedScale(float invertScale, float densityInvertScale) {
+        sOverrideInvertedScale = invertScale;
+        sOverrideDensityInvertScale = densityInvertScale;
     }
 
     /** @see #sOverrideInvertedScale */
@@ -633,6 +686,11 @@ public class CompatibilityInfo implements Parcelable {
         return sOverrideInvertedScale;
     }
 
+    /** @see #sOverrideDensityInvertScale */
+    public static float getOverrideDensityInvertedScale() {
+        return sOverrideDensityInvertScale;
+    }
+
     /**
      * Compute the frame Rect for applications runs under compatibility mode.
      *
@@ -693,6 +751,8 @@ public class CompatibilityInfo implements Parcelable {
             if (applicationDensity != oc.applicationDensity) return false;
             if (applicationScale != oc.applicationScale) return false;
             if (applicationInvertedScale != oc.applicationInvertedScale) return false;
+            if (applicationDensityScale != oc.applicationDensityScale) return false;
+            if (applicationDensityInvertedScale != oc.applicationDensityInvertedScale) return false;
             return true;
         } catch (ClassCastException e) {
             return false;
@@ -713,6 +773,8 @@ public class CompatibilityInfo implements Parcelable {
         if (hasOverrideScaling()) {
             sb.append(" overrideInvScale=");
             sb.append(applicationInvertedScale);
+            sb.append(" overrideDensityInvScale=");
+            sb.append(applicationDensityInvertedScale);
         }
         if (!supportsScreen()) {
             sb.append(" resizing");
@@ -734,6 +796,8 @@ public class CompatibilityInfo implements Parcelable {
         result = 31 * result + applicationDensity;
         result = 31 * result + Float.floatToIntBits(applicationScale);
         result = 31 * result + Float.floatToIntBits(applicationInvertedScale);
+        result = 31 * result + Float.floatToIntBits(applicationDensityScale);
+        result = 31 * result + Float.floatToIntBits(applicationDensityInvertedScale);
         return result;
     }
 
@@ -748,6 +812,8 @@ public class CompatibilityInfo implements Parcelable {
         dest.writeInt(applicationDensity);
         dest.writeFloat(applicationScale);
         dest.writeFloat(applicationInvertedScale);
+        dest.writeFloat(applicationDensityScale);
+        dest.writeFloat(applicationDensityInvertedScale);
     }
 
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)
@@ -769,5 +835,61 @@ public class CompatibilityInfo implements Parcelable {
         applicationDensity = source.readInt();
         applicationScale = source.readFloat();
         applicationInvertedScale = source.readFloat();
+        applicationDensityScale = source.readFloat();
+        applicationDensityInvertedScale = source.readFloat();
+    }
+
+    /**
+     * A data class for holding scale factor for width, height, and density.
+     */
+    public static final class CompatScale {
+
+        public final float mScaleFactor;
+        public final float mDensityScaleFactor;
+
+        public CompatScale(float scaleFactor) {
+            this(scaleFactor, scaleFactor);
+        }
+
+        public CompatScale(float scaleFactor, float densityScaleFactor) {
+            mScaleFactor = scaleFactor;
+            mDensityScaleFactor = densityScaleFactor;
+        }
+
+        @Override
+        public boolean equals(@Nullable Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (!(o instanceof CompatScale)) {
+                return false;
+            }
+            try {
+                CompatScale oc = (CompatScale) o;
+                if (mScaleFactor != oc.mScaleFactor) return false;
+                if (mDensityScaleFactor != oc.mDensityScaleFactor) return false;
+                return true;
+            } catch (ClassCastException e) {
+                return false;
+            }
+        }
+
+        @Override
+        public String toString() {
+            StringBuilder sb = new StringBuilder(128);
+            sb.append("mScaleFactor= ");
+            sb.append(mScaleFactor);
+            sb.append(" mDensityScaleFactor= ");
+            sb.append(mDensityScaleFactor);
+            return sb.toString();
+        }
+
+        @Override
+        public int hashCode() {
+            int result = 17;
+            result = 31 * result + Float.floatToIntBits(mScaleFactor);
+            result = 31 * result + Float.floatToIntBits(mDensityScaleFactor);
+            return result;
+        }
     }
 }
diff --git a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
index 1ef552f670f4..4aea70c6dd64 100644
--- a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
+++ b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
@@ -68,7 +68,6 @@ import static android.view.WindowManager.TRANSIT_CHANGE;
 import static android.view.WindowManager.TRANSIT_PIP;
 import static android.view.WindowManager.TRANSIT_TO_FRONT;
 import static android.view.WindowManagerPolicyConstants.KEYGUARD_GOING_AWAY_FLAG_TO_LAUNCHER_CLEAR_SNAPSHOT;
-
 import static com.android.internal.protolog.ProtoLogGroup.WM_DEBUG_CONFIGURATION;
 import static com.android.internal.protolog.ProtoLogGroup.WM_DEBUG_DREAM;
 import static com.android.internal.protolog.ProtoLogGroup.WM_DEBUG_FOCUS;
@@ -5631,6 +5630,15 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
         }
     }
 
+    void registerCompatScaleProvider(@CompatScaleProvider.CompatScaleModeOrderId int id,
+            @NonNull CompatScaleProvider provider) {
+        mCompatModePackages.registerCompatScaleProvider(id, provider);
+    }
+
+    void unregisterCompatScaleProvider(@CompatScaleProvider.CompatScaleModeOrderId int id) {
+        mCompatModePackages.unregisterCompatScaleProvider(id);
+    }
+
     /**
      * Returns {@code true} if the process represented by the pid passed as argument is
      * instrumented and the instrumentation source was granted with the permission also
diff --git a/services/core/java/com/android/server/wm/CompatModePackages.java b/services/core/java/com/android/server/wm/CompatModePackages.java
index c6978fd59134..e906b185bae7 100644
--- a/services/core/java/com/android/server/wm/CompatModePackages.java
+++ b/services/core/java/com/android/server/wm/CompatModePackages.java
@@ -20,7 +20,10 @@ import static com.android.internal.protolog.ProtoLogGroup.WM_DEBUG_CONFIGURATION
 import static com.android.server.wm.ActivityTaskManagerDebugConfig.TAG_ATM;
 import static com.android.server.wm.ActivityTaskManagerDebugConfig.TAG_WITH_CLASS_NAME;
 import static com.android.server.wm.ActivityTaskSupervisor.PRESERVE_WINDOWS;
+import static com.android.server.wm.CompatScaleProvider.COMPAT_SCALE_MODE_SYSTEM_FIRST;
+import static com.android.server.wm.CompatScaleProvider.COMPAT_SCALE_MODE_SYSTEM_LAST;
 
+import android.annotation.NonNull;
 import android.app.ActivityManager;
 import android.app.AppGlobals;
 import android.app.GameManagerInternal;
@@ -32,6 +35,7 @@ import android.compat.annotation.Overridable;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.IPackageManager;
 import android.content.res.CompatibilityInfo;
+import android.content.res.CompatibilityInfo.CompatScale;
 import android.content.res.Configuration;
 import android.os.Build;
 import android.os.Handler;
@@ -332,6 +336,8 @@ public final class CompatModePackages {
     private final HashMap<String, Integer> mPackages = new HashMap<>();
     private final CompatHandler mHandler;
 
+    private final SparseArray<CompatScaleProvider> mProviders = new SparseArray<>();
+
     public CompatModePackages(ActivityTaskManagerService service, File systemDir, Handler handler) {
         mService = service;
         mFile = new AtomicFile(new File(systemDir, "packages-compat.xml"), "compat-mode");
@@ -441,13 +447,38 @@ public final class CompatModePackages {
 
     public CompatibilityInfo compatibilityInfoForPackageLocked(ApplicationInfo ai) {
         final boolean forceCompat = getPackageCompatModeEnabledLocked(ai);
-        final float compatScale = getCompatScale(ai.packageName, ai.uid);
+        final CompatScale compatScale = getCompatScaleFromProvider(ai.packageName, ai.uid);
+        final float appScale = compatScale != null
+                ? compatScale.mScaleFactor
+                : getCompatScale(ai.packageName, ai.uid, /* checkProvider= */ false);
+        final float densityScale = compatScale != null ? compatScale.mDensityScaleFactor : 1f;
         final Configuration config = mService.getGlobalConfiguration();
         return new CompatibilityInfo(ai, config.screenLayout, config.smallestScreenWidthDp,
-                forceCompat, compatScale);
+                forceCompat, appScale, densityScale);
     }
 
     float getCompatScale(String packageName, int uid) {
+        return getCompatScale(packageName, uid, /* checkProvider= */ true);
+    }
+
+    private CompatScale getCompatScaleFromProvider(String packageName, int uid) {
+        for (int i = 0; i < mProviders.size(); i++) {
+            final CompatScaleProvider provider = mProviders.valueAt(i);
+            final CompatScale compatScale = provider.getCompatScale(packageName, uid);
+            if (compatScale != null) {
+                return compatScale;
+            }
+        }
+        return null;
+    }
+
+    private float getCompatScale(String packageName, int uid, boolean checkProviders) {
+        if (checkProviders) {
+            final CompatScale compatScale = getCompatScaleFromProvider(packageName, uid);
+            if (compatScale != null) {
+                return compatScale.mScaleFactor;
+            }
+        }
         final UserHandle userHandle = UserHandle.getUserHandleForUid(uid);
         if (mGameManager == null) {
             mGameManager = LocalServices.getService(GameManagerInternal.class);
@@ -487,6 +518,36 @@ public final class CompatModePackages {
         return 1f;
     }
 
+    void registerCompatScaleProvider(@CompatScaleProvider.CompatScaleModeOrderId int id,
+            @NonNull CompatScaleProvider provider) {
+        synchronized (mService.mGlobalLock) {
+            if (mProviders.contains(id)) {
+                throw new IllegalArgumentException("Duplicate id provided: " + id);
+            }
+            if (provider == null) {
+                throw new IllegalArgumentException("The passed CompatScaleProvider "
+                        + "can not be null");
+            }
+            if (!CompatScaleProvider.isValidOrderId(id)) {
+                throw new IllegalArgumentException(
+                        "Provided id " + id + " is not in range of valid ids for system "
+                                + "services [" + COMPAT_SCALE_MODE_SYSTEM_FIRST + ","
+                                + COMPAT_SCALE_MODE_SYSTEM_LAST + "]");
+            }
+            mProviders.put(id, provider);
+        }
+    }
+
+    void unregisterCompatScaleProvider(@CompatScaleProvider.CompatScaleModeOrderId int id) {
+        synchronized (mService.mGlobalLock) {
+            if (!mProviders.contains(id)) {
+                throw new IllegalArgumentException(
+                        "CompatScaleProvider with id (" + id + ") is not registered");
+            }
+            mProviders.remove(id);
+        }
+    }
+
     private static float getScalingFactor(String packageName, UserHandle userHandle) {
         if (CompatChanges.isChangeEnabled(DOWNSCALE_90, packageName, userHandle)) {
             return 0.9f;
diff --git a/services/core/java/com/android/server/wm/CompatScaleProvider.java b/services/core/java/com/android/server/wm/CompatScaleProvider.java
new file mode 100644
index 000000000000..5474ecec381a
--- /dev/null
+++ b/services/core/java/com/android/server/wm/CompatScaleProvider.java
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.server.wm;
+
+import android.annotation.IntDef;
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.content.res.CompatibilityInfo.CompatScale;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/**
+ * An interface for services that need to provide compatibility scale different than
+ * the default android compatibility.
+ */
+public interface CompatScaleProvider {
+
+    /**
+     * The unique id of each provider registered by a system service which determines the order
+     * it will execute in.
+     */
+    @IntDef(prefix = { "COMPAT_SCALE_MODE_" }, value = {
+        // Order Ids for system services
+        COMPAT_SCALE_MODE_SYSTEM_FIRST,
+        COMPAT_SCALE_MODE_GAME,
+        COMPAT_SCALE_MODE_PRODUCT,
+        COMPAT_SCALE_MODE_SYSTEM_LAST, // Update this when adding new ids
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    @interface CompatScaleModeOrderId {}
+
+    /**
+     * The first id, used by the framework to determine the valid range of ids.
+     * @hide
+     */
+    int COMPAT_SCALE_MODE_SYSTEM_FIRST = 0;
+
+    /**
+     * TODO(b/295207384)
+     * The identifier for {@link android.app.GameManagerInternal} provider
+     * @hide
+     */
+    int COMPAT_SCALE_MODE_GAME = 1;
+
+    /**
+     * The identifier for a provider which is specific to the type of android product like
+     * Automotive, Wear, TV etc.
+     * @hide
+     */
+    int COMPAT_SCALE_MODE_PRODUCT = 2;
+
+    /**
+     * The final id, used by the framework to determine the valid range of ids. Update this when
+     * adding new ids.
+     * @hide
+     */
+    int COMPAT_SCALE_MODE_SYSTEM_LAST = COMPAT_SCALE_MODE_PRODUCT;
+
+    /**
+     * Returns {@code true} if the id is in the range of valid system services
+     * @hide
+     */
+    static boolean isValidOrderId(int id) {
+        return (id >= COMPAT_SCALE_MODE_SYSTEM_FIRST && id <= COMPAT_SCALE_MODE_SYSTEM_LAST);
+    }
+
+    /**
+     * @return an instance of {@link CompatScale} to apply for the given package
+     */
+    @Nullable
+    CompatScale getCompatScale(@NonNull String packageName, int uid);
+}
diff --git a/services/tests/wmtests/src/com/android/server/wm/CompatScaleProviderTest.java b/services/tests/wmtests/src/com/android/server/wm/CompatScaleProviderTest.java
new file mode 100644
index 000000000000..96e3cb1030ce
--- /dev/null
+++ b/services/tests/wmtests/src/com/android/server/wm/CompatScaleProviderTest.java
@@ -0,0 +1,166 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.wm;
+
+import static com.android.dx.mockito.inline.extended.ExtendedMockito.mock;
+import static org.junit.Assert.assertThrows;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import android.platform.test.annotations.Presubmit;
+
+import androidx.test.filters.SmallTest;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.InOrder;
+
+/**
+ * Tests for the {@link CompatScaleProvider} interface.
+ * See {@link CompatModePackages} class for implementation.
+ *
+ * Build/Install/Run:
+ * atest WmTests:CompatScaleProviderTest
+ */
+@SmallTest
+@Presubmit
+public class CompatScaleProviderTest extends SystemServiceTestsBase {
+    private static final String TEST_PACKAGE = "compat.mode.packages";
+    static final int TEST_USER_ID = 1;
+
+    private ActivityTaskManagerService mAtm;
+
+    /**
+     * setup method before every test.
+     */
+    @Before
+    public void setUp() {
+        mAtm = mSystemServicesTestRule.getActivityTaskManagerService();
+    }
+
+    /**
+     * Registering a {@link CompatScaleProvider} with an invalid id should throw an exception.
+     */
+    @Test
+    public void registerCompatScaleProviderWithInvalidId() {
+        CompatScaleProvider compatScaleProvider = mock(CompatScaleProvider.class);
+        assertThrows(
+                IllegalArgumentException.class,
+                () ->  mAtm.registerCompatScaleProvider(-1, compatScaleProvider)
+        );
+    }
+
+    /**
+     * Registering a {@code null} {@link CompatScaleProvider} should throw an exception.
+     */
+    @Test
+    public void registerCompatScaleProviderFailIfCallbackIsNull() {
+        assertThrows(
+                IllegalArgumentException.class,
+                () ->  mAtm.registerCompatScaleProvider(
+                            CompatScaleProvider.COMPAT_SCALE_MODE_PRODUCT, null)
+        );
+    }
+
+    /**
+     * Registering a {@link CompatScaleProvider} with a already registered id should throw an
+     * exception.
+     */
+    @Test
+    public void registerCompatScaleProviderFailIfIdIsAlreadyRegistered() {
+        CompatScaleProvider compatScaleProvider = mock(CompatScaleProvider.class);
+        mAtm.registerCompatScaleProvider(CompatScaleProvider.COMPAT_SCALE_MODE_PRODUCT,
+                compatScaleProvider);
+        assertThrows(
+                IllegalArgumentException.class,
+                () ->  mAtm.registerCompatScaleProvider(
+                            CompatScaleProvider.COMPAT_SCALE_MODE_PRODUCT, compatScaleProvider)
+        );
+        mAtm.unregisterCompatScaleProvider(CompatScaleProvider.COMPAT_SCALE_MODE_PRODUCT);
+    }
+
+    /**
+     * Successfully registering a {@link CompatScaleProvider} with should result in callbacks
+     * getting called.
+     */
+    @Test
+    public void registerCompatScaleProviderSuccessfully() {
+        CompatScaleProvider compatScaleProvider = mock(CompatScaleProvider.class);
+        mAtm.registerCompatScaleProvider(CompatScaleProvider.COMPAT_SCALE_MODE_PRODUCT,
+                compatScaleProvider);
+        mAtm.mCompatModePackages.getCompatScale(TEST_PACKAGE, TEST_USER_ID);
+        verify(compatScaleProvider, times(1)).getCompatScale(TEST_PACKAGE, TEST_USER_ID);
+        mAtm.unregisterCompatScaleProvider(CompatScaleProvider.COMPAT_SCALE_MODE_PRODUCT);
+    }
+
+    /**
+     * Unregistering a {@link CompatScaleProvider} with a unregistered id should throw an exception.
+     */
+    @Test
+    public void unregisterCompatScaleProviderFailIfIdNotRegistered() {
+        assertThrows(
+                IllegalArgumentException.class,
+                () ->  mAtm.unregisterCompatScaleProvider(
+                            CompatScaleProvider.COMPAT_SCALE_MODE_PRODUCT)
+        );
+    }
+
+    /**
+     * Unregistering a {@link CompatScaleProvider} with an invalid id should throw an exception.
+     */
+    @Test
+    public void unregisterCompatScaleProviderFailIfIdNotInRange() {
+        assertThrows(
+                IllegalArgumentException.class,
+                () ->  mAtm.unregisterCompatScaleProvider(-1)
+        );
+    }
+
+    /**
+     * Successfully unregistering a {@link CompatScaleProvider} should stop the callbacks from
+     * getting called.
+     */
+    @Test
+    public void unregisterCompatScaleProviderSuccessfully() {
+        CompatScaleProvider compatScaleProvider = mock(CompatScaleProvider.class);
+        mAtm.registerCompatScaleProvider(CompatScaleProvider.COMPAT_SCALE_MODE_PRODUCT,
+                compatScaleProvider);
+        mAtm.unregisterCompatScaleProvider(CompatScaleProvider.COMPAT_SCALE_MODE_PRODUCT);
+        mAtm.mCompatModePackages.getCompatScale(TEST_PACKAGE, TEST_USER_ID);
+        verify(compatScaleProvider, never()).getCompatScale(TEST_PACKAGE, TEST_USER_ID);
+    }
+
+    /**
+     * Order of calling {@link CompatScaleProvider} is same as the id that was used for
+     * registering it.
+     */
+    @Test
+    public void registerCompatScaleProviderRespectsOrderId() {
+        CompatScaleProvider gameModeCompatScaleProvider = mock(CompatScaleProvider.class);
+        CompatScaleProvider productCompatScaleProvider = mock(CompatScaleProvider.class);
+        mAtm.registerCompatScaleProvider(CompatScaleProvider.COMPAT_SCALE_MODE_GAME,
+                gameModeCompatScaleProvider);
+        mAtm.registerCompatScaleProvider(CompatScaleProvider.COMPAT_SCALE_MODE_PRODUCT,
+                productCompatScaleProvider);
+        mAtm.mCompatModePackages.getCompatScale(TEST_PACKAGE, TEST_USER_ID);
+        InOrder inOrder = inOrder(gameModeCompatScaleProvider, productCompatScaleProvider);
+        inOrder.verify(gameModeCompatScaleProvider).getCompatScale(TEST_PACKAGE, TEST_USER_ID);
+        inOrder.verify(productCompatScaleProvider).getCompatScale(TEST_PACKAGE, TEST_USER_ID);
+    }
+}